Wrench for rock drill bits



May.2 3, 1950 e. coPLl-:N 2,508,664 I WRENCH -F-OR ROCK DRILL BITS Filed Nov. 5, 1945 /N vE/v T014?. Gf/vf J. Conf/v ATTORNEY.

Patented May 23, 1950 ITED STATES PATENT' OFFICE 1 Claim.

This invention relates to a rock drill bit wrench. The bits of modern rock drills are threaded onto the extremity of the drill steel shank and, when the bits become dull, it is necessary to remove them from the steel shanks and replace them with a sharpened bit. This procedure has been exceedingly dilcult to do due to the fact that the pounding from the pneumatic drill sets the bits so firmly on the steel that it is almost impossible to remove them. The difficulty is increased by the fact that there are no surfaces on the drill bit whichv can be adequately gripped by a conventional wrench and by the fact that the bits are hardened to such an extent that they cannot be gripped with toothed wrenches, such as pipe wrenches, alligator wrenches and the like.

The principal object of this invention is to provide in a single, simple and highly eflicient tool means for rmly holding the drill steel shank in combination with means for gripping and rotating the drill bit thereon so that the bit may be easily and rapidly removed.

Another object of the invention is to construct the improved wrench as a single unit so that there will be no loose, separate pieces or parts which may become lost or displaced.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efliciency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

Fig. 1 is a plan View of the improved Wrench as it would appear when in place on the steel and bit;

Fig. 2 is a side view thereof;

Fig. 3 is a bottom view thereof;

Fig. 4 illustrates the side opposite to that of Fig. 2; and

Fig. 5 is a cross-section, taken on the line 5 5, Fig. 1.

In the drawing a typical drill steel shank is indicated in broken line at I0 with its drill bit at II. Drill steels have various cross sections such as round, hexagonal, cross, etc. in each case, however, the steel terminates in a rounded shank carrying a concentric, left-hand threaded stud which threads into a similarly threaded socket in the bit II.

I member I2 is formed` with anarcuate dove-tailed socket I4 in its lower surface extending concentrically of the axis of thek arc of the frame members. The lower frame member I3 is provided with a corresponding arcuate dove-tailed spline I5 which is slidably mounted in the socket I4 so that the two frame members may be rotated relative to each other about a common axis.

The upper frame member terminates at one extremity in a hingle tongue I6 to which an upper handle I'I is hinged by means of a hinge pin I8, the extremity of the handle being bifurcated to t over the tongue I6. One extremity of the lower frame member is provided with a similar hinge tongue I9 upon which a lower handle 20 is hingedly mounted by. means of a second hinge pin 2l. The lower handle is similarly bifurcated to t over its hinge tongue I9. Both hinge pins are secured in place in any desired manner, such as by means of suitable Cotter keys 22.

The upper frame member is designed for gripping the drill bit I I and the lower frame member is designed for gripping the shank of the drill steel Ill.

For gripping the bit, the extremity of the handle Il is provided with a cam 23 positioned eccentrically about the axis of the pin I8. The opposite extremity of the upper frame member I2 terminates in an inwardly extending gripping lug 24. A spacing boss 25 extends inwardly from the upper member intermediate the cam 23 and the lug 24.

It can be readily seen from Fig. 1 of the drawing that the lug 24 ts into one of the concave sides of the bit II and, when the handle I'I is rotated in the direction of the arrow B in Fig. 1, the cam 23 will forcibly engage the concavity on the opposite side of the drill bit to clamp the latter tightly against the lug 24. The boss 25 engages in the intermediate concave side of the drill bit to assist in centering the latter in the frame member.

For gripping the shank of the drill steel, the handle member 20 is provided with a toothed cam 26 positioned eccentrically of the axis of the hinge pin 2| so that when the handle 20 is swung in the direction of the arrow A, Fig. 1, the toothed surface of the cam 26 will be forced against the surface of the drill steel I0. 'I'he opposite extremity of the lower frame member I3 terminates in a downwardly and inwardly ex- 3 tending toothed jaw 21 forming an abutment against which the shank I is forced by the action of the toothed cam 26. The lower frame member is also provided with a centering boss 2B similar to the boss 25 of the upper frame member.

The hinge pin I3 carries a projecting head 29 which extends into the path of the lower frame member I3 and prevents the two frame members from' being turned to a position Where the spline I5 will leave its socket I4.

In use, the wrench is opened to the position indicated in broken line in Fig. 1. The drill steel and bit are laid in the open socket formed by the frame members I2 and I3. The handle 20 is then swung to the solid line position of Fig. 1 to bring its toothed cam 2B against the shank I0 and the handle Il is similarly swung in the direction of the arrow B to cause its cam 23 to engage the bit i I. The two handle members are now forced toward each other in the directions of the arrows A and B causing the upper frame member to slide around the arc of the lower frame member so that the shank IB and the bit II will be rotated in opposite directions about the axis of the bit to loosen the bit from the threads of the shank.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, Within the scope of the appended claim, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

A wrench for removing grooved drill bits from rock drill steels comprising: two similar, semicircular frame members lying flat against each other; an arcuate dovetailed groove extending medially of one frame member throughout its length; a corresponding arcuate dovetailed spline extending medially of the other frame member and being slidably mounted in said arcuate groove so that said two frame members may be rotated about a common axis relative to each other; a first hinge pin positioned at the extremity of the rst frame member; a second hinge pin positioned at the opposite extremity of the second frame member; a toothed ratchet cam rotatably mounted on the rst hinge pin and adapted to engage said drill steel; an eccentric arcuate cam rotatably mounted on the second hinge pin and adapted to engage in a groove in said drill bit; a gripping lug extending radially inward from' said second frame member so as to engage a groove in said bit oppositely to said arcuate cam; a toothed jaw extending outwardly from the side of said first frame member and thence inwardly toward the axis thereof to engage the side of said drill steel oppositely to said tooth ratchet cam; and an operating lever eX- tending from each cam.

GENE JOSEPH COPLEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,476,341 Le Bus et al Dec. 4, 1923 1,572,986 Brewster Feb. 16, 1926 1,599,808 Coates Sept. 14, 1926 1,855,143 Williams Apr. 19, 1932 2,283,625 Coplen May 19, 1942 FOREIGN PATENTS Number Country Date 423,313 Great Britain Jan. 30, 1935 

